[Feature] How about to add flan-t5 series models

[YuriyGavrilov]

Just about to add this models to list.

[aarnphm]

vllm support encoder-decoder models, but not flan-t5 afaict.

tbh SLM are a lot better now and outperform t5, such as phi3, and gemma would suffice

[bojiang]

It seems T5 are supported by llamacpp. ggml-org/llama.cpp#8141
@aarnphm Any idea?

[aarnphm]

I mean we can add support for t5,

my feeling is for encoder-decoder models there must be better option?